Rectal balloon apparatus with pressure relieving lumen and sensors

PRIOR RELATED APPLICATIONS

0001This application is a continuation of pending U.S. application Ser. No. 12/707,389, which is a continuation-in-part of each of the following co-pending U.S. Applications, all of which are hereby incorporated by reference for all purposes in their entirety:

0002(1) U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007

0003(2) U.S. application Ser. No. 11/933,018 filed on Oct. 31, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007;

0004(3) U.S. application Ser. No. 12/034,470 filed on Feb. 20, 2008, which is a continuation-in-part of U.S. application Ser. No. 11/933,018 filed on Oct. 31, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007;

0005(4) U.S. application Ser. No. 11/966,544 filed on Dec. 28, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/933,018 filed on Oct. 31, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007;

0006(5) U.S. application Ser. No. 12/141,270 filed on Jun. 18, 2008, which is a continuation-in-part of U.S. application Ser. No. 12/034,470 filed on Feb. 20, 2008, which is a continuation-in-part of U.S. application Ser. No. 11/933,018 filed on Oct. 31, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007;

0007(6) U.S. application Ser. No. 12/410,639 filed on Mar. 25, 2009; and

0008(7) U.S. application Ser. No. 12/412,017 filed on Mar. 26, 2009, which is a continuation-in-part of U.S. application Ser. No. 11/966,544 filed on Dec. 28, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/933,018 filed on Oct. 31, 2007, which is a continuation-in-part of U.S. application Ser. No. 11/623,702 filed on Jan. 16, 2007.

FEDERALLY SPONSORED RESEARCH STATEMENT

N/A

REFERENCE TO MICROFICHE APPENDIX

N/A

BACKGROUND OF THE INVENTION

00111. Field of the Invention

0012The present invention relates to rectal balloons that are used for immobilizing the region surrounding the prostate.

00132. Description of the Related Art

0014Treatment of prostate cancer using radiation therapy is difficult due to the prostate's position near radiation-sensitive tissues, and is further complicated by prostate motion. Adenocarcinoma of the prostate commonly occurs in the posterior portion of the prostate gland, which is in very close proximity to the rectal wall. To date, external beam radiation treatment, urethrograms, CT scans and magnetic resonance imaging (MRI) have all been used to visually localize the prostate, as well as the normal critical structures in the surrounding area.

0015U.S. Pat. No. 5,476,095, issued on Dec. 19, 1995 to Schnall et al., proposes an insertable pickup probe for use in providing diagnostic MRI images. The pickup probe, in its preferred embodiment, is proposed for use in imaging the male prostate and comprises an elongated shaft supporting an inflatable patient interface balloon at its distal end. The interface balloon comprises an inner balloon and an outer balloon, between which a receiving coil is positioned. A lumen for air supply is provided in the shaft for expanding the inner balloon against the outer balloon to place the receiving coil in close proximity to the area of interest in order to provide MRI images.

0016Typically, the planning of radiation therapy for the treatment of prostate cancer involves the patient undergoing a CT-based simulation scan of the pelvis to determine the location of the prostate gland. In the simulation phase, the patient is placed on CT equipment that is preferably similar to the radiation treatment equipment (except that it does not generate the high energy radiation beam). The simulation equipment is positioned to simulate the delivery of the sequence of treatment beams prescribed by the treating oncologist. Normally, during the simulation procedure, CT images are acquired. These CT images allow the oncologist to locate the position of the tumor and help to facilitate the composition of a radiation treatment plan. This treatment plan delineates the positions of the radiation equipment components for delivery of the treatment beams.

0017During the actual treatment phase, the patient is placed in the same position on the treatment equipment as in the simulation scans. Radiation-emitting devices are generally known and used for radiation therapy in the treatment of patients. Typically, a radiation therapy device includes a gantry, which can be swiveled around a horizontal axis of rotation in the course of a therapeutic treatment. A linear accelerator is located in the gantry for generating a high-energy radiation beam for therapy. During treatment, the radiation beam is provided by this equipment and is delivered to the patient at the precise location as delineated by the physician during simulation. A further feature of radiation therapy involves portal images, which are commonly used in radiation therapy to verify and record the patient tumor location. Portal images include manual (film) and electronic images (EPI) taken before and/or after the treatment.

0018During external beam radiation therapy, radiation is directed to the target prostate which is near the rectal wall. A misdirected radiation beam may perforate the rectal wall causing radiation proctitus (rectal bleeding). This toxicity is related to the total radiation dose prescribed and the volume of the anterior rectal wall receiving a high radiation dose. A major factor limiting radiation oncologists' attempts to reduce the volume of the anterior rectal wall receiving a high radiation dose is the position of the prostate gland as well as the intrinsic motion up to 5 mm in the anterior to posterior direction caused by rectal peristalsis. Accordingly, oncologists generally will add a margin to the radiation field in order to ensure that the entire prostate gland receives the prescription dose. This margin is typically on the order of 5 to 15 mm. As a consequence, lower doses of radiation may need to be used so as not to overexpose radiation sensitive structures. However, this may lead to inadequate radiation treatment and a higher probability of local cancer recurrence.

0019U.S. Patent Publication No. 2003/0028097, published on Feb. 6, 2003 to D'Amico et al., proposes an insertable probe for immobilizing a region of interest during staging and radiation therapy thereof. In particular, a balloon is proposed having a rectangular cross section connected to a shaft. The shaft extends to an end of the balloon so as to allow fluid flow through an interior of the shaft and into the balloon so as to selectively inflate the balloon once the balloon is installed into the rectal cavity. The balloon, shaft and handle are bonded together so that they move radially as a single unit when torque is applied. A syringe is provided which connects the shaft and serves as an air pump to deliver a volume-limited amount of air to the air lumen of the shaft to the balloon. A stop cock is provided to maintain the air within the balloon.

0020One of the problems with the subject of U.S. Patent Publication No. 2003/0028097 is the discomfort associated with installing the rectal balloon within the rectal cavity. In particular, a relatively sturdy and wide diameter shaft is connected to a relatively large thick-walled balloon. Because the balloon is not supported by anything other than by the shaft, the balloon is formed of a relatively rugged and thick material. Because of the relatively large size of the shaft and the thick material of the rectangular-cross section balloon, the installation of the rectal balloon creates a large amount of discomfort for a patient. It is often difficult for the medical personnel to know exactly how far within the rectum the balloon has been installed. It is difficult to achieve a standardized and fixed position of the balloon during each and every use. The medical personnel must generally approximate the desired position of the balloon within the rectal cavity. As such, a need has developed whereby the rectal balloon can be formed of a minimal diameter shaft and of a balloon of relatively thin material.

0021When the rectal balloon of U.S. Patent Publication No. 2003/0028097 is in an inflated condition, the outer surface is generally round. As such, the prostate will tend to balance on the curved surface rather than be properly seated thereon. Since seating is important for proper use, this device requires that the physician approximate a seated position rather than providing any feedback of the seated position. When the balloon is in a curved inflated condition, the prostate will have a tendency to slide to one side of the balloon. As such, a need developed to provide a rectal balloon that retains the prostate in a proper seated position when the balloon is in a fully inflated condition.

0022As discussed above, a very important consideration when treating patients using radiation therapy is that the proper dose of radiation reaches the treatment site. This is very important whether the treatment method utilizes implanted radiation seeds or external beams of radiation. Excessive dosing of the patient can lead to severe side effects including impotence and urinary incontinence. A proper treatment plan should deliver an adequate amount of radiation to the treatment site while minimizing the dose delivered to the surrounding tissues.

0023U.S. Pat. No. 6,963,771, issued on Nov. 8, 2005 to Scarantino et al., describes a method, system and implantable device for radiation dose verification. The method includes (a) placing at least one wireless implantable sensor in a first subject at a target location; (b) administering a first dose of radiation therapy into the first subject; (c) obtaining radiation data from the at least one wireless implantable sensor; and (d) calculating a radiation dose amount received by the first subject at the target location based on the radiation data obtained from the at least one wireless sensor during and/or after exposure to the first administered dose of radiation to determine and/or verify a dose amount of radiation delivered to the target location.

0024U.S. Pat. No. 7,361,134, issued on Apr. 22, 2008 to Rozenfeld et al., proposes a method of determining the dose rate of a radiation source including locating three or more detectors in the vicinity of a source. Each of the detectors provides an output indicative of the amount of radiation received from the source and determines the location of the source from at least some of the detector outputs. International Pub. No. WO 2008/148150, published on Dec. 11, 2008 to Rozenfeld, proposes a semiconductor radiation sensor.

0025U.S. Patent Publication No. 2009/0236510, published on Sep. 24, 2009 to Lacroix et al., proposes a radiation dosimeter for measuring a relative dose of a predetermined radiation type within a detection region by using a plurality of scintillating optical fibers. U.S. Patent Publication No. 2006/0094923, published on May 4, 2006 to Mate, proposes a marker comprising a wireless transponder configured to wirelessly transmit a location signal in response to a wirelessly transmitted excitation energy.

0026A significant cause of patient discomfort associated with rectal balloons of the prior art is the buildup of gas pressure when the balloon is inserted into the rectum. This buildup of gas pressure can also affect the ability to properly seat the balloon in a desired position.

0027The above discussed U.S. Pat. Nos. 5,476,095; 6,963,771; and 7,361,134; and Pub. Nos. U.S. 2003/0028097; 2006/0094923; and 2009/0236510; and International Pub No. WO 2008/148150 are hereby incorporated by reference for all purposes in their entirety.

0028A need exists for a rectal balloon apparatus that relieves rectal gas pressure prior to or during inflation of the balloon. A need also exists for a rectal balloon apparatus that senses the amount of radiation received at or near a treatment site, and that also detects the motion of the rectal balloon apparatus and/or the means used by the apparatus to sense the radiation.

BRIEF SUMMARY OF THE INVENTION

0029A rectal balloon apparatus comprises a shaft having a fluid passageway extending therethrough. A lumen may be positioned with or be integral to the shaft for movement of rectal gas or other rectal fluids. A flexible tip with one or more openings may be disposed on the end of the shaft and/or the rectal gas relieving lumen inserted into the rectum. The shaft may have a locking device that is slidable longitudinally along the shaft. The locking device may be locked at a desired indicia on the shaft to fix the amount of movement of the shaft into the rectum. In one embodiment, a splitting device disposed with the ends of the shaft and the rectal gas relieving lumen that are not inserted into the rectum may split the lumen from the fluid passageway of the shaft. The lumen port on the splitting device may have a luer lock device for placement of a lumen port cap to prevent the back flow of rectal fluids. A syringe may be positioned with the luer lock to flush the lumen.

0030A balloon may be affixed over an end of the shaft such that the fluid passageway communicates with an interior of the balloon. The balloon may be movable from a non-inflated condition to an inflated condition. A radiation detecting sensor may be positioned at any location with the balloon, the shaft, and/or the rectal gas relieving lumen for sensing the amount of radiation delivered. A motion detecting sensor may be positioned at any location with the balloon, the shaft, and/or the rectal gas relieving lumen for sensing the amount of motion or movement of the balloon or surrounding area, such as the part of the rectal wall near the prostate, the shaft, the rectal gas relieving lumen, the radiation sensor, any fiducial markers, and/or any other part of the apparatus. The balloon may have a generally laterally flat surface when in the inflated condition, with a longitudinal groove formed in the laterally flat surface. One or more fiducial markers may be positioned at any location with the balloon, the shaft, and/or the rectal gas relieving lumen. A fiducial marker may be positioned with the flexible tip at the end of the shaft and/or lumen inserted into the rectum. Other types of sensors may be positioned with the balloon, the shaft and/or the lumen. A processor may be used to interpret the information from the different sensors and fiducial markers.

BRIEF DESCRIPTION OF THE DRAWINGS

0031A better understanding of the present invention can be obtained with the following detailed descriptions of the various disclosed embodiments in the drawings:

0032<figref idref="DRAWINGS">FIG. 1</figref> is a side elevational view showing a rectal balloon apparatus in an uninflated condition.

0033<figref idref="DRAWINGS">FIG. 2</figref> is a side elevational view of a rectal balloon apparatus in an inflated condition.

0034<figref idref="DRAWINGS">FIG. 3</figref> is an isolated view showing the compact folding of the balloon over the end of the shaft.

0035<figref idref="DRAWINGS">FIG. 4</figref> is a top view of an inflated balloon showing the application of fiducial markers, radiation detecting sensors, and motion detecting sensors.

0036<figref idref="DRAWINGS">FIG. 5</figref> is a side view, partially transparent, of a balloon in a first inflated condition.

0037<figref idref="DRAWINGS">FIG. 6</figref> is a side view, partially transparent, of a balloon in a second inflated condition.

0038<figref idref="DRAWINGS">FIG. 7</figref> is a side view of a locking device in the locked position with the rectal balloon apparatus positioned within the anal canal.

0039<figref idref="DRAWINGS">FIG. 7A</figref> is a perspective isolated view of the locking device in the unlocked position.

0040<figref idref="DRAWINGS">FIG. 8</figref> is side view of the balloon of the rectal balloon apparatus positioned within the rectum and in an inflated condition.

0041<figref idref="DRAWINGS">FIG. 9</figref> is side view of the balloon of the rectal balloon apparatus and in an inflated condition.

0042<figref idref="DRAWINGS">FIG. 10</figref> is side view, partially transparent, of a balloon in the inflated condition with a rectal gas relieving lumen integral with a shaft, and radiation detecting sensors and motion detecting sensors positioned with the balloon.

0043<figref idref="DRAWINGS">FIG. 11</figref> is side view of a balloon in the inflated condition with a rectal gas relieving lumen inside the fluid passageway of a shaft, a splitting device, and a lumen port cap positioned with the lumen port of the splitting device.

0044<figref idref="DRAWINGS">FIG. 12</figref> is an enlarged view of the balloon of <figref idref="DRAWINGS">FIG. 11</figref>.

0045<figref idref="DRAWINGS">FIG. 13</figref> is an enlarged view of the splitting device of <figref idref="DRAWINGS">FIG. 11</figref> showing the lumen port cap disposed with a luer lock.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

0046<figref idref="DRAWINGS">FIG. 1</figref> shows a rectal balloon apparatus <b>10</b> comprising a shaft <b>12</b> having a fluid passageway extending therethrough. A balloon <b>14</b> is affixed over the end <b>16</b> of the shaft <b>12</b>. The balloon <b>14</b> is shown in an uninflated or deflated condition. The fluid passageway of the shaft <b>12</b> can communicate with the interior of the balloon <b>14</b>. Also shown is the locking device <b>13</b>, which is shown in more detail in <figref idref="DRAWINGS">FIGS. 7 and 7A</figref> and discussed below in detail therewith. The locking device <b>13</b> serves to assure reproducibility in the positioning of the balloon <b>14</b> during radiation therapy.

0047The shaft <b>12</b> may be a generally longitudinal shaft which has the fluid passageway extending through the center thereof. As used herein, fluid may mean gas, such as air, or liquid. The shaft <b>12</b> may be made of a flexible material. A valve assembly <b>22</b> may be affixed to the shaft <b>12</b> opposite the balloon <b>14</b>. The valve assembly <b>22</b> can have a variety of configurations. <figref idref="DRAWINGS">FIG. 1</figref> illustrates the valve assembly <b>22</b> as an inline valve assembly configuration. The valve assembly <b>22</b> may also be an angled valve assembly configuration. The valve assembly <b>22</b> includes a stopcock <b>26</b>. A valve <b>28</b> facilitates the ability of the stopcock <b>26</b> to open and close so as to selectively allow the fluid to pass into the shaft <b>12</b>. A port <b>30</b> allows the valve assembly <b>22</b> to be connected to a supply of the fluid. When the stopcock <b>26</b> is opened by the rotation of the valve <b>28</b>, the fluid will flow through the valve assembly <b>22</b>, through the interior passageway of the shaft <b>12</b> and into the interior of the balloon <b>14</b>. The valve <b>28</b> can then be closed so as to maintain the inflated configuration of the balloon <b>14</b>. When the procedure is finished and the fluid needs to be removed from the balloon <b>14</b>, the valve <b>28</b> of stopcock <b>26</b> can then be opened so as to allow for the release of fluid therethrough.

0048The opposite end <b>16</b> of the shaft <b>12</b> may contact the end <b>32</b> of the balloon <b>14</b>. The end <b>16</b> may be suitably curved or dome-shaped so as to allow the shaft <b>12</b> to facilitate the introduction of the balloon <b>14</b> into the rectal cavity. The shaft <b>12</b> may have indicia <b>34</b> formed therealong. It can be seen that the indicia <b>34</b> has numerical references associated therewith. These numerical references are indicative of the distance that the balloon <b>14</b> has been inserted into the rectum. As such, the indicia <b>34</b> provide a clear indication to the medical personnel of the desired location of the rectal balloon <b>14</b>. An anal dilator ring <b>19</b> is shown adjacent an end of the balloon <b>14</b>.

0049<figref idref="DRAWINGS">FIG. 2</figref> illustrates an isolated view of the apparatus <b>10</b> after being installed within the rectum. The fluid can be introduced through the valve assembly <b>22</b> and through the interior passageway of the shaft <b>12</b> so as to inflate the balloon <b>14</b>. The balloon <b>14</b> may have a seating area <b>15</b> so that the prostate can be properly positioned thereon. When the balloon <b>14</b> is installed and inflated, the prostate may reside on the flat surface <b>15</b> in a seated position. After the procedure has been completed, the balloon <b>14</b> can be deflated and easily pulled outwardly of the rectum in its deflated condition. In <figref idref="DRAWINGS">FIG. 2</figref>, it can be seen that the locking device <b>13</b> has been moved along the shaft <b>12</b> (from its position in <figref idref="DRAWINGS">FIG. 1</figref>) to indicia <b>34</b>, specifically at the number “<b>20</b>.” This serves to assure that the balloon <b>14</b> will be in a proper position during subsequent radiation treatments.

0050<figref idref="DRAWINGS">FIG. 3</figref> shows that the balloon <b>14</b> is neatly folded and compressed over the outer diameter of the shaft <b>12</b>. The shaft <b>12</b> may have a rounded end abutting the end <b>32</b> of the balloon <b>14</b>. As such, a comfortable rounded profile may be provided at this end <b>32</b>. The balloon <b>14</b> may be pre-vacuumed during production to produce a minimal profile during use. The anal dilator ring <b>19</b> is placed over the shaft <b>12</b>.

0051<figref idref="DRAWINGS">FIG. 4</figref> is a top view of the balloon <b>14</b> showing the area of the balloon <b>14</b> that preferably engages with the prostate. Central seating area <b>46</b> for the prostate is shown as having a groove <b>52</b> formed thereon. The groove <b>52</b> may be generally rectangular-shaped and may engage with the tip of the prostate, reducing lateral motion. Other configurations of the groove <b>52</b> are contemplated. The central seating area <b>46</b> and the groove <b>52</b> enhance the holding stability of the balloon <b>14</b>. The head portion <b>17</b> of the balloon <b>14</b> may be generally tapered. This shape makes insertion of the balloon <b>14</b> into the rectum easier for medical personnel and more comfortable for the patient. The balloon <b>14</b> may have a thermally welded bond <b>53</b> connecting it to the shaft <b>12</b>. Other forms of bonding are also contemplated.

0052A first radiation detecting sensor <b>70</b> may be located within the groove <b>52</b> of the central seating area <b>46</b>. The sensor <b>70</b> allows the treating physician to determine the real time delivery dose of radiation being received at the treatment area when the balloon <b>14</b> is in place. The sensor <b>70</b> may located in the middle of the groove <b>52</b>. This location is ideally centrally located on the prostate when the balloon <b>14</b> is in place. However, the radiation detecting sensor <b>70</b> may be positioned at any other location with the balloon, the shaft, or a rectal gas relieving lumen (not shown). A second radiation detecting sensor <b>70</b>B is shown disposed with the shaft, and a third radiation detecting sensor <b>70</b>A is shown positioned with the balloon surface. A radiation detecting sensor may be positioned with any surface of the balloon, the shaft, or a rectal gas relieving lumen. It is also contemplated that a radiation detecting sensor may be positioned unattached in the interior of the balloon.

0053As shown in <figref idref="DRAWINGS">FIG. 5</figref>, a fourth radiation detecting sensor <b>70</b>C is positioned on the curved surface <b>44</b> of the balloon that is not adjacent the treatment area. Although only one radiation detecting sensor <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C is preferably used, it is contemplated that more than one radiation sensor <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C may be used. By positioning the sensor <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C near or adjacent to the prostate or other targeted anatomies, an accurate measurement of the radiation delivered to the prostate and/or other targeted anatomies, such as seminal vesicles, may be achieved. The sensors <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C can be chosen from any of the available sensors that enable the user to monitor radiation dosage. International Pub No. WO 2008/148150 proposes the preferable type of semiconductor radiation sensor that is contemplated. U.S. Pat. No. 7,361,134 also proposes a type of radiation sensor that is contemplated. It is also contemplated that a radiation sensor using scintillating fiber optics may be used. The sensor <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C may be positioned with the balloon, the shaft, or the gas relieving lumen with an adhesive, such as an epoxy glue. However, other attachment means are contemplated as are known in the art.

0054Six fiducial markers <b>72</b> are shown positioned with the balloon <b>14</b>. Although a plurality of markers <b>72</b> are shown, it is contemplated that there may be only one or more fiducial markers <b>72</b>. It is contemplated that one or more fiducial markers <b>72</b>A may be positioned anywhere with the balloon, the shaft, or the gas relieving lumen (not shown). A fiducial marker <b>72</b>A is shown positioned at the end of the shaft. The fiducial markers <b>72</b>, <b>72</b>A may be made of a tungsten material, which may be detected by an MRI or CT scan. Other materials that may be visible on an MRI or CT scan are also contemplated, such as barium sulfate. Fiducial markers in powder or liquid form are contemplated. Through the use of these fiducial markers <b>72</b>, <b>72</b>A on the balloon <b>14</b> or shaft <b>12</b>, a treating physician may get a clear image of the position of anterior and posterior walls of the rectum, and/or the position of the rectum relative to the prostate. Fiducial markers <b>72</b> may be positioned in spaced relation to each other with the top surface of the balloon <b>14</b>. For illustrative purposes, three of the fiducial markers <b>72</b> are positioned in linear alignment on one side of the groove <b>52</b>. Another three fiducial markers <b>72</b> are arranged on the opposite side of the groove <b>52</b>. Other combinations and locations of markers <b>72</b>, <b>72</b>A are contemplated. A further benefit can be realized by utilizing an additional fiducial marker in the form of a gold seed marker implanted into the prostate. The gold seed marker combined with the fiducial markers <b>72</b> allows for triangulation to make certain that the balloon, rectum, and prostate is in the correct position for treatment.

0055A first motion detecting sensor <b>73</b> is shown within the groove <b>52</b> of the central seating area <b>46</b>. The motion detecting sensor <b>73</b> allows the treating physician to determine the movement of any of the radiation sensors <b>70</b>, <b>70</b>A, <b>70</b>B, <b>70</b>C, fiducial markers <b>72</b>, <b>72</b>A, the shaft, the gas relieving lumen, the balloon surface and the surrounding area, such as the part of the rectal wall near the prostate, and/or any other part of the apparatus. Although the motion detecting sensor <b>73</b> is shown in the groove <b>52</b>, one or more motion detecting sensors <b>73</b> may be positioned at any other location with the balloon, the shaft, or the gas relieving lumen (not shown). A second motion detecting sensor <b>73</b>A is shown placed at a different location with the surface the balloon. As shown in <figref idref="DRAWINGS">FIG. 5</figref>, a third motion detecting sensor <b>73</b>B may be positioned with the curved surface of the balloon that is not adjacent the treatment area. Although only one motion detecting sensor <b>73</b>, <b>73</b>A, <b>73</b>B is preferably used, it is contemplated that more than one motion detecting sensor <b>73</b>, <b>73</b>A, <b>73</b>B may be used. The motion detecting sensors <b>73</b>, <b>73</b>A, <b>73</b>B may be selected from any of the available sensors that enable the user to detect motion. It is contemplated that disposable sensors may be used. It is also contemplated that an electromagnetic type motion detecting sensor may be used. Other types of sensors are contemplated.

0056<figref idref="DRAWINGS">FIG. 5</figref> is an isolated view of the balloon <b>14</b> as inflated to a first inflated condition. In this condition, the balloon <b>14</b> has a central seating portion <b>46</b>, a head portion <b>17</b> and a posterior portion <b>44</b>. When inflated, the central seating area <b>46</b> has a lateral flatness for the prostate to rest upon. The lateral flatness of the seating area <b>46</b> will prevent the prostate from sliding to one side or the other, and not deform the prostate. The bottom portion <b>44</b> is rounded and contacts the rectal wall. The head portion <b>17</b> is generally tapered so as to facilitate easier insertion of the balloon <b>14</b>. The material of the balloon <b>14</b> may be formed of a non-latex material so as to avoid allergic reactions. The shaft <b>12</b> is shown extending into the interior of the balloon <b>14</b>. A plurality of holes <b>48</b> may be formed in the shaft <b>12</b> through which the balloon <b>14</b> is filled with air or other fluid.

0057For all embodiments shown in all Figures, the balloons, such as balloon <b>14</b> in <figref idref="DRAWINGS">FIG. 5</figref>, may have a posterior or bottom portion, such as bottom portion <b>44</b>, that is made from a different thickness film material than the seating portion, such as seating portion <b>46</b>. By way of example, the posterior portion <b>44</b> may be made with a thicker material than the seating portion <b>46</b>. The thicker material may allow a support structure for the balloon <b>14</b>, and the thinner material may allow for the seating portion <b>46</b> to maintain its shape or have a bulge, such as bulge <b>47</b> shown in <figref idref="DRAWINGS">FIG. 6</figref>. It is also contemplated that the posterior portion <b>44</b> may be thinner than the seating portion <b>46</b>. The balloon may be made from two or more materials with different thicknesses attached together, such as by thermally welded bond. It is also contemplated that the balloon may be made from two or more materials with the same thickness but with different elasticity properties, such as different modulus of elasticity.

0058It can be seem that each of the holes <b>48</b> is spaced from and offset by 90.degree. from an adjacent hole around the diameter of shaft <b>12</b>. Other arrangements and orientations are contemplated. A total of six holes may preferably be formed in the shaft <b>12</b> within balloon <b>14</b> so as to allow the fluid to pass from an interior of shaft <b>12</b> to the interior of the balloon <b>14</b>. Other numbers of holes are contemplated. This arrangement of holes <b>48</b> facilitates complete extraction of the fluid from the balloon <b>14</b>. Under certain circumstances, one of the holes may become clogged or blocked by contact between the body and the balloon, and the staged arrangement assures that the unblocked holes <b>48</b> allow the fluid to continue to be easily extracted. In <figref idref="DRAWINGS">FIG. 5</figref>, it can be seen that additional fiducial markers <b>72</b> are positioned on the opposite side of balloon <b>14</b>.

0059<figref idref="DRAWINGS">FIG. 6</figref> is an isolated view of the balloon <b>14</b> as inflated to a second inflated condition. In the second inflated condition, the balloon <b>14</b> has a first bulge <b>47</b> formed at the head portion <b>17</b>. The balloon also has a laterally flat seating portion <b>46</b>. The first bulge <b>47</b> can be utilized in certain conditions to better isolate the prostate and stabilize the seminal vesicles.

0060Turning to <figref idref="DRAWINGS">FIG. 7</figref>, the prostate immobilizer <b>10</b> has a shaft <b>12</b> having a fluid passageway <b>64</b> extending therethrough, a balloon <b>14</b> extending over an end <b>16</b> of the shaft <b>12</b> such that the fluid passageway <b>64</b> communicates with an interior <b>66</b> of the balloon <b>14</b>, a rectal gas relieving lumen <b>60</b> extending within the shaft <b>12</b> so as have an end <b>62</b> opening adjacent an end <b>68</b> of the balloon <b>14</b>, and a locking device <b>13</b> for locking a position of the shaft <b>12</b> of the prostate immobilizer <b>10</b>. The device <b>13</b> is adjustably slidable along the shaft <b>12</b>. The device <b>13</b> serves to assure uniformity in the positioning of the balloon <b>14</b> in the rectal cavity <b>2</b> adjacent the prostate <b>3</b> during radiation therapy.

0061The end <b>16</b> of the shaft <b>12</b> is adjacent the end <b>68</b> of the balloon <b>14</b>. The end <b>16</b> of the shaft <b>12</b> is suitably curved or domed-shaped so as to allow the shaft <b>12</b> to facilitate the introduction of the balloon <b>14</b> into the rectal cavity <b>2</b>. The prostate immobilizer <b>10</b> is inserted into the rectal cavity <b>2</b> through anus <b>1</b>. The shaft indicia <b>34</b> has numerical references associated therewith. The numerical references are indicative of the distance that the balloon <b>14</b> is inserted into the anus <b>1</b>. The indicia <b>34</b> provide a clear indication to medical personnel of the position of the balloon <b>14</b> in the rectal cavity <b>2</b> for repeatability for subsequent treatments. The balloon <b>14</b> can be removed and re-inserted into the rectal cavity <b>2</b>. The device <b>13</b> is affixed to the shaft <b>12</b> so that the balloon <b>14</b> will be repositioned for a same distance into the rectal cavity <b>2</b> adjacent the prostate <b>3</b>.

0062The locking device <b>13</b> is shown as positioned where indicia <b>34</b> number “<b>25</b>”. The anal dilator ring <b>19</b> is affixed to the shaft <b>12</b> adjacent the balloon <b>14</b>. The anal dilator ring <b>19</b> may displace the anal verge so as to displace the anal tissue and delineate the anatomy. The anal dilator ring <b>19</b> has a diameter greater than a diameter of the shaft <b>12</b>.

0063Once the balloon <b>14</b> is positioned in a desired location adjacent the prostate <b>3</b>, medical personnel position the locking device <b>13</b> so that it is adjacent the anus <b>1</b> and holds the prostate immobilizer <b>10</b> in position. The balloon <b>14</b> is shown as in inflated condition. The seating area <b>15</b> is positioned adjacent the prostate <b>3</b> when in the rectal cavity <b>2</b>. The prostate immobilizer <b>10</b> is inserted and removed from the anus <b>1</b> in the deflated condition. The lateral flatness of the seating area <b>15</b> resists and inhibits the prostate <b>3</b> motion. The rounded outer surface of the balloon <b>14</b> generally contacts the wall of the rectal cavity <b>2</b>. The balloon <b>14</b> can be formed of a non-latex material, such as polyurethane, so as to avoid allergic reactions.

0064The gas relieving lumen <b>60</b>, although shown on the interior of the shaft <b>12</b>, can be in any other orientation, such as on the outer surface of the shaft <b>12</b>, that allows for the removal of rectal gas. End <b>62</b> of the lumen <b>60</b> has one or more openings that allow for rectal gas or other bodily fluids to escape from the rectal cavity <b>2</b> and out of the lumen <b>60</b>. A one-way valve can be included along the length of the lumen <b>60</b> so as to only allow rectal gas or other bodily fluids to pass from the rectal cavity <b>2</b> to the outside environment through the gas relieving lumen <b>60</b>. The interior of the shaft <b>12</b> may be in fluid communication with the interior <b>66</b> of the balloon <b>14</b> so as to allow fluids to pass into and out of the interior <b>66</b> of the balloon <b>14</b> for inflation and deflation.

0065During subsequent radiation treatments, the locking device <b>13</b> can be affixed to the shaft <b>12</b> in the same position as shown in <figref idref="DRAWINGS">FIG. 7</figref>. As such, when the balloon <b>14</b> is inserted, the shaft <b>12</b> can be urged forward until the locking device <b>13</b> contacts the entrance of the anus. The medical personnel may be confident that the balloon <b>14</b> is in the proper position. This is accomplished accurately regardless of any change of medical personnel, any squeezing of the sphincter muscles by the patient, and any variations in the amount of lubrication jelly that is used. Repeatability is typically assured. Reproducibility is particularly important when a radiation sensor is used in conjunction with the balloon. It is desirable that the radiation detecting sensor be in the substantially same location each time that it is detecting radiation. When the locking device is affixed to the shaft, it will not be easily displaced. The smooth contour of the outer surface provides comfort to the patient.

0066In <figref idref="DRAWINGS">FIG. 7A</figref>, the locking device <b>13</b> is in an unlocked position prior to attaching to the shaft <b>12</b> (not shown). The device <b>13</b> has a positioning member <b>18</b> and a locking member <b>38</b>. The positioning member <b>18</b> has a head portion <b>20</b> and a stem portion <b>320</b>. The stem portion <b>320</b> is integrally formed adjacent an end <b>24</b> of the head portion <b>20</b>. The positioning member <b>18</b> has a channel <b>340</b> formed therein. The channel <b>340</b> extends through each of the head portion <b>20</b> and the stem portion <b>320</b>. The positioning member <b>18</b> has a longitudinal split <b>36</b> formed therein. The longitudinal split <b>36</b> extends through the head portion <b>20</b>. The longitudinal split <b>36</b> communicates with the channel <b>340</b>. The locking member <b>38</b> has a locked position and an unlocked position. The locking member <b>38</b> is hingedly connected to the stem portion <b>320</b> of the positioning member <b>18</b>. The head portion <b>20</b> of the positioning member <b>18</b> has a hemispherical shape. The stem portion <b>320</b> of the positioning member <b>18</b> has an outer surface flush with an outer surface of the head portion <b>20</b>. The longitudinal split <b>36</b> extends for the entire length of the head portion <b>20</b>. The longitudinal split <b>36</b> has a width slightly greater than the diameter of the shaft <b>12</b>. This allows the shaft <b>12</b> to be introduced into the channel <b>340</b>.

0067The stem portion <b>320</b> has an outer surface <b>40</b> that is flush with an outer surface of the head portion <b>20</b>. As such, the locking device <b>13</b> has smooth contours on the outer surface thereof. The stem portion <b>320</b> has a lip <b>480</b> extending and angling upwardly and outwardly of the outer surface <b>40</b>. The lip <b>480</b> is generally adjacent to the wall of the longitudinal split <b>36</b> of the head portion <b>20</b>. A curved surface <b>470</b> is formed on the interior of the stem portion <b>320</b> and has a plurality of ribs formed thereon. The curved surface <b>470</b> devices a portion of the channel <b>340</b>. The longitudinally-extending ribs on the curved surface <b>470</b> of channel <b>340</b> provide a structure that can suitably grip the outer surface of the shaft so as to facilitate the ability to fix the position of the locking device <b>13</b> on shaft <b>12</b>.

0068The locking member <b>38</b> is hingedly connected to the stem portion <b>320</b>. The locking member <b>50</b> includes a latch <b>50</b> that has an edge that will engage the lip <b>480</b> of the stem portion <b>320</b>. The inner surface <b>51</b> of the locking member <b>50</b> includes a curved area <b>53</b>. Curved area <b>53</b> has ribs to grip and generally corresponds with the location of the curved surface <b>470</b> of stem portion <b>320</b>. As such, curved area <b>53</b> will cooperate with the curved surface <b>470</b> so as to define the channel <b>340</b> of the positioning member <b>18</b> when the locking member <b>38</b> is in a locked position. The locking member <b>38</b> also has an inner surface <b>52</b> which will reside in proximity with the end <b>24</b> of the head portion <b>20</b>.

0069<figref idref="DRAWINGS">FIG. 8</figref> shows an anatomical side view of the rectal balloon apparatus <b>10</b> positioned within a patient's rectum. The balloon <b>14</b> is shown in an inflated condition and positioned up against and between the anterior wall <b>92</b> and the posterior wall <b>94</b> of the rectum <b>96</b>. It can be seen that the balloon <b>14</b> is positioned adjacent the prostate <b>90</b>. Additionally, it can be seen that a radiation detecting sensor <b>70</b> and a motion detecting sensor <b>73</b> are generally positioned adjacent the anterior wall <b>92</b> of the rectum <b>96</b>. It is also contemplated that a plurality of fiducial markers may also be positioned adjacent the anterior wall and/or the posterior wall <b>94</b> of the rectum <b>96</b>. Thus, when a treating physician can determine the position of the plurality of fiducial markers he or she may obtain a clear image of the contours of the anterior wall <b>92</b> and the posterior wall <b>94</b> of the rectum <b>96</b> by essentially “connecting the dots.” The radiation sensor <b>70</b> may be used to detect the amount of radiation being received by the target areas, such as the rectal-prostate interface. The motion detecting sensor <b>73</b> may detect the movement of any of the sensors, markers, balloon surface or surrounding area, balloon shaft, or other part of the apparatus. <figref idref="DRAWINGS">FIG. 8</figref> also shows the importance of the flexible aspect of the shaft <b>12</b> and the utilization of the locking device <b>13</b>.

0070The locking device <b>13</b> provides an initial indication of the depth of positioning of the balloon <b>14</b>. The lateral flatness of the balloon <b>14</b> is assuredly positioned against the prostate.

0071The radiation detecting sensor <b>70</b> is thereby attempted to be positioned at the same location during all treatments. The sensor <b>70</b> can then be used to determine the amount of radiation delivered during each treatment, both daily radiation doses and accumulative radiation for the course of treatment.

0072<figref idref="DRAWINGS">FIG. 9</figref> is a side view of a rectal balloon apparatus <b>110</b> having a balloon <b>114</b> with a rectal gas relieving lumen <b>116</b> positioned with a surface of the shaft <b>112</b>. The gas release lumen <b>116</b> extends to an exterior of the balloon <b>114</b>. First opening <b>118</b> allows rectal gas or other fluids to pass from an exterior of the balloon <b>114</b> into the lumen <b>116</b>. The rectal gas passes through the lumen <b>116</b> to another opening at the opposite end of the lumen <b>116</b>, and into the atmosphere. The lumen <b>116</b> will have a portion extending interior of the balloon <b>114</b>. The ends of the balloon <b>114</b> will be sealed around the lumen <b>116</b> and the shaft <b>112</b>. A flexible lumen tip with ports, like lumen tip <b>156</b> shown in <figref idref="DRAWINGS">FIG. 12</figref>, may be positioned over first opening <b>118</b>. The flexible lumen tip with ports may provide for patient comfort when the shaft <b>112</b> is inserted into the rectum, and prevent bodily material from entering and clogging or obstructing the gas release lumen <b>116</b>.

0073A first radiation detecting sensor <b>140</b> may be located with the balloon <b>114</b>. The sensor <b>140</b> is preferably located adjacent the prostate when the balloon <b>114</b> is in place. However, the radiation detecting sensor <b>140</b> may be positioned at any other location with the balloon <b>114</b>, the shaft <b>112</b>, or the lumen <b>116</b>, including the flexible lumen tip, such as tip <b>156</b> in <figref idref="DRAWINGS">FIG. 12</figref>. A second radiation detecting sensor <b>140</b>A is shown disposed with the shaft, and a third radiation detecting sensor <b>140</b>B is shown positioned with the lumen. It is also contemplated that a radiation detecting sensor may be positioned unattached in the interior of the balloon. As shown in <figref idref="DRAWINGS">FIG. 10</figref>, a fourth radiation detecting sensor <b>140</b>C may be positioned on the surface of the balloon that is not adjacent the treatment area. International Pub No. WO 2008/148150 proposes a type of semiconductor radiation sensor that is contemplated. U.S. Pat. No. 7,361,134 also proposes a type of radiation sensor that is contemplated. It is also contemplated that a radiation sensor using scintillating fiber optics may be used. Although only one radiation detecting sensor <b>140</b>, <b>140</b>A, <b>140</b>B, <b>140</b>C is preferably used, it is contemplated that more than one radiation sensor <b>140</b>, <b>140</b>A, <b>140</b>B, <b>140</b>C may be used.

0074Six fiducial markers <b>142</b> are shown positioned with the balloon <b>114</b>. Although a plurality of markers <b>142</b> are shown, it is contemplated that there may be only one or more fiducial markers <b>142</b>. It is contemplated that one or more fiducial markers <b>142</b> may be positioned anywhere with the balloon <b>114</b>, the shaft <b>112</b>, or the lumen <b>116</b>, including a lumen tip with ports. A fiducial marker <b>142</b>A is shown positioned at the end of the shaft <b>112</b>. The fiducial markers <b>142</b>, <b>142</b>A may be made of a tungsten material, which may be detected by an MRI or CT scan. Other materials that may be visible on an MRI or CT scan are also contemplated, such as barium sulfate. Fiducial markers in powder or liquid form are contemplated. Other combinations and locations of markers <b>142</b>, <b>142</b>A are contemplated.

0075A first motion detecting sensor <b>143</b> is shown positioned with the balloon <b>114</b>. The motion detecting sensor <b>143</b> allows the treating physician to determine the movement of the any of the radiation detecting sensors <b>140</b>, <b>140</b>A, <b>140</b>B, <b>140</b>C, fiducial markers <b>142</b>, <b>142</b>A, balloon shaft <b>112</b>, lumen <b>116</b>, or the balloon <b>114</b> and the surrounding area, such as the part of the rectal wall near the prostate. One or more motion detecting sensors <b>143</b> may be positioned at any location with the balloon, the shaft, or the lumen. A second motion detecting sensor <b>143</b>A is shown placed at a different location with the surface the balloon. The motion detecting sensors <b>143</b>, <b>143</b>A may be selected from any of the available sensors that enable the user to detect motion.

0076<figref idref="DRAWINGS">FIG. 10</figref> is a side view of a rectal balloon apparatus <b>120</b> having a balloon <b>124</b> with the gas pressure relieving activity of the rectal gas release lumen <b>126</b> integrated with the shaft <b>122</b>. The shaft <b>122</b> extends to an exterior of the balloon <b>124</b>, and has an opening <b>128</b> outside of the balloon <b>124</b>. A one-way valve means <b>130</b> may be formed within the shaft <b>122</b>. The one-way valve means <b>130</b> allows rectal gas to pass from the exterior of the balloon <b>124</b>, into the opening <b>128</b>, and through the one-way valve means <b>130</b> into the shaft <b>122</b>. The one-way valve means <b>130</b> prevents fluid or rectal gas from escaping through opening <b>128</b> from the interior of the shaft <b>122</b>. The one-way valve means <b>130</b> operates to allow bodily gas to escape through the interior of the shaft <b>122</b> when the balloon <b>124</b> is installed in the rectum. After the rectal gas has escaped, air or other fluid may be introduced into the balloon <b>124</b> so as to inflate the balloon <b>124</b>, while at the same time, closing the one-way valve means <b>130</b>. It is also contemplated that there may be no one-way valve means. A flexible lumen tip with ports, like tip <b>156</b> in <figref idref="DRAWINGS">FIG. 12</figref>, may be positioned over opening <b>128</b>. The flexible tip or cap with ports may provide for patient comfort when the shaft <b>122</b> is inserted into the rectum, and prevent bodily material from entering the shaft <b>122</b>. Radiation detecting sensors <b>140</b>, <b>140</b>A, <b>140</b>B, <b>140</b>C, fiducial markers <b>142</b>, <b>142</b>A, and motion detecting sensors <b>143</b>, <b>143</b>A may be positioned with the shaft <b>122</b> and/or the balloon <b>124</b> of <figref idref="DRAWINGS">FIG. 10</figref> as shown in <figref idref="DRAWINGS">FIG. 9</figref>. A sensor and/or fiducial marker may be positioned with a flexible tip with ports positioned over first opening <b>118</b> of lumen <b>116</b>.

0077<figref idref="DRAWINGS">FIG. 11</figref> shows a balloon <b>154</b> positioned with shaft <b>162</b> having a fluid passageway for inflating and deflating the balloon <b>154</b>, and the lumen <b>152</b> (best shown in <figref idref="DRAWINGS">FIG. 12</figref>) for allowing gas pressure to escape from beyond the end of the balloon. The shaft <b>162</b> has ports in the area of the balloon for inflation and deflation, such as previously described. A flexible tip or cap <b>156</b> is positioned on the end of the lumen <b>152</b>. Rectal gas may enter the port <b>168</b> in the tip <b>156</b>, and flow through the lumen <b>152</b>, escaping through the lumen port <b>150</b> on the splitting device <b>158</b>. One or more lumen tip ports <b>168</b> are contemplated. As shown in greater detail in <figref idref="DRAWINGS">FIG. 13</figref>, the splitting means <b>158</b> splits the lumen <b>152</b> from the fluid passageway of the shaft <b>162</b>. Returning to <figref idref="DRAWINGS">FIG. 11</figref>, anal dilator or collar <b>164</b> may be constructed of a hard material and locked over the shaft <b>162</b>. The collar <b>164</b> may have a hinge and a locking mechanism. Valve assembly <b>170</b> includes a control knob <b>172</b>. Turning the control knob <b>172</b> serves to close the valve assembly <b>170</b> so as to selectively allow the fluid to pass into the shaft <b>162</b>. A port <b>174</b> allows the valve assembly to be connected to a supply of the fluid.

0078Turning to <figref idref="DRAWINGS">FIG. 12</figref>, radiation detecting sensors <b>140</b>, <b>140</b>A, <b>140</b>B, <b>140</b>C, fiducial markers <b>142</b>, <b>142</b>A, and motion detecting sensors <b>143</b>, <b>143</b>A may be positioned with the shaft <b>162</b> and/or the balloon <b>154</b> similarly as shown in <figref idref="DRAWINGS">FIG. 9</figref>. A sensor and/or fiducial marker may be positioned with flexible lumen tip <b>156</b>.

0079In <figref idref="DRAWINGS">FIG. 13</figref>, the lumen port <b>150</b> on the splitting device <b>158</b> may have a lip formation <b>182</b> for placement of a lumen port cap <b>180</b>. A luer lock formation or device is contemplated. It is contemplated that the cap <b>180</b> may be threadingly attached with the lumen port <b>150</b>. Other attachment means as are known in the art are contemplated. The cap advantageously prevents fluid from escaping the lumen <b>152</b>.

0080The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and system, and the construction and method of operation may be made without departing from the spirit of the invention.